1. Field of the Invention
The present invention relates to a navigation apparatus providing guidance for traffic lane changes.
2. Description of the Related Art
In conventional vehicle navigation apparatuses, a route to a destination is determined by search and guidance is provided to assist travel along the determined route. At an intersection or a branch point, guidance, such as turning right or turning left, is provided for following the determined route. A system which announces a right turn lane and/or a left turn lane is disclosed, for example, in Japanese Unexamined Patent Application Publication No. 62-093617. Other related art photographs the road surface ahead of the vehicle using a camera and an image, such as an arrow painted on the road surface which shows branching, is processed to recognize the traffic lane in which the vehicle is traveling, and recommends a lane chance if appropriate, as disclosed, for example, in Japanese Unexamined Patent Application Publication No. (“Kokai”) 10-281795.
However, with conventional vehicle navigation systems, drivers had to judge the current traffic situation since traffic lanes were not recognized at an intersection and/or branch point where the vehicle is to change lanes. With the apparatus disclosed in Kokai 10-281,795, to prompt traffic lane changes, the camera photographs the road surface in front of the vehicle, and traffic lanes are recognized. However, as the vehicle changes lanes, the system does not recognise whether or not another vehicle is approaching from behind, thus leaving the driver with the burden of determining the timing for a traffic lane change.